People aged 40 to 44 are now able to book an appointment to receive their COVID-19 vaccine.
Bookings opened at noon on Thursday.
Health Minister Robin Swann welcomed the announcement.
“Vaccination is by far our best defence against COVID-19 and is essential to our goal of getting Northern Ireland out of lockdown on a sustainable basis,” he said.
Close to one million COVID-19 vaccines have been administered in Northern Ireland.
People making bookings are asked to be patient, as demand for appointments will be strong.
The ongoing roll-out of the vaccination programme will continue to be dependent on the availability of vaccine supplies.
People in Northern Ireland aged 18-29 who do not have an underlying medical condition will be offered an alternative vaccine, when this is available.
You can book an appointment online at the Health and Social Care booking website or by telephoning 0300 200 7813.